HIV-1 infection depletes human CD34+CD38- hematopoietic progenitor cells via pDC-dependent mechanisms

Chronic human immunodeficiency virus-1 (HIV-1) infection in patients leads to multilineage hematopoietic abnormalities or pancytopenia. The deficiency in hematopoietic progenitor cells (HPCs) induced by HIV-1 infection has been proposed, but the relevant mechanisms are poorly understood. We report here that both human CD34(+)CD38(-) early and CD34(+)CD38(+) intermediate HPCs were maintained in the bone marrow (BM) of humanized mice. Chronic HIV-1 infection preferentially depleted CD34(+)CD38(-) early HPCs in the BM and reduced their proliferation potential in vivo in both HIV-1-infected patients and humanized mice, while CD34(+)CD38(+) intermediate HSCs were relatively unaffected. Strikingly, depletion of plasmacytoid dendritic cells (pDCs) prevented human CD34(+)CD38(-) early HPCs from HIV-1 infection-induced depletion and functional impairment and restored the gene expression profile of purified CD34(+) HPCs in humanized mice. These findings suggest that pDCs contribute to the early hematopoietic suppression induced by chronic HIV-1 infection and provide a novel therapeutic target for the hematopoiesis suppression in HIV-1 patients.